1. Field of the Invention
The present invention relates to image processing for protecting the copyright of the image or the like.
2. Related Background Art
Standardization of motion image encoding technology is progressing rapidly in recent years. There are already determined encoding standards such as MPEG-1, 2, H.261 and H.263 (these encoding methods being internationally standardized by ISO (International Organization for Standardization) and ITU (International Telecommunication Union)), and international standardization is being in progress for MPEG-4 as the general-purpose next-generation multi media encoding standard usable in various areas such as computer, broadcasting and communication. These encoding technologies have advanced the digitization of images, stimulating rapid progress in the accumulation and communication of motion image data.
For example in the MPEG-4, a motion image scene of a given instant is regarded as a group of constituent objects such as xe2x80x9cpersonxe2x80x9d, xe2x80x9cautomobilexe2x80x9d, xe2x80x9cbackgroundxe2x80x9d, xe2x80x9cmusicxe2x80x9d, xe2x80x9cvideoxe2x80x9d etc., and highly efficient encoding of the motion image data is achieved by applying adaptive encoding for each object.
In the multi-object encoding technology such as MPEG-4, a scene is represented by the combination of compression encoded objects. Consequently another scene can be easily represented in the MPEG-4 data, by re-utilizing object data from other MPEG-4 data.
With the spreading of such digital encoding standards as mentioned above, the issue of copyright protection is being strongly requested from the contents-related businesses. The issue is that good contents cannot be safely provided with the standard that cannot ensure satisfactory copyright protection.
This issue is serious in MPEG-4, because the encoding is executed for each object in MPEG-4 as explained above and can therefore be manipulated or modified. Consequently, in the multi-object encoding as in MPEG-4, the protection of intellectual property in the unit of each object is an obvious request in consideration of smooth re-utilization of each object, and the protection of portrait right is also requested in case the object is a person.
Therefore, for the purpose of protecting the copyright of a part of a motion image, there is conceived a method of temporarily stopping the decoding of the motion image in order not to reproduce such part of the motion image. More specifically, in consideration of the copyright or portrait right in the motion image, the decoding is stopped in a portion relating to such rights, and is started again after such portion is over.
Such method is however associated with the following drawbacks.
For the motion image, there is generally employed encoding methods utilizing interframe correlation. Among these methods, well known are H.261, H.263, MPEG-1, 2 and MPEG-4. In these methods, the encoding is basically executed by motion compensation, referring to a preceding frame or preceding and succeeding frames in time.
FIG. 1 shows the mode of reproduction by H.261, H.263 etc., in which I indicates a frame for which infraframe encoding is executed while P indicates a frame for which interframe encoding is executed. In FIG. 1, TIME indicates lapse of time; SECURITY shows the period (black zone) during which the decoding is stopped; CODE indicates the arrangement of frames in the order of encoding; and DISPLAY indicates the arrangement of frames in the order of display.
It is now assumed that the decoding is stopped for the encoded data P4 to P9 for the purpose of protection (security) of the intellectual property right (for example copyright). The decoding of the motion image is stopped at P3, and the image is thereafter not displayed until the decoding is re-started. Simultaneous with the stopping of the decoding, the writing of the encoded data into the buffer is stopped, so that the encoded data P4 to P9 are discarded. Therefore, when the decoding is re-started from P10 after the image protection period, the decoding process from P10 cannot be executed properly since P9, to be referred to by P10, is already discarded, so that the image in each frame is perturbed or the decoding operation is interrupted in a period of P10 to P13 before the decoding of the intraframe encoded I1.
Also, the MPEG-1, 2 or 4 encoding method employs bidirectional motion compensation executing prediction forward and backward in time.
FIG. 2 shows the encoding mode in such method. B indicates a frame for which bidirectional interframe encoding is executed. In FIG. 2, TIME indicates lapse of time; SECURITY shows the period (black zone) during which the decoding is stopped; CODE indicates the arrangement of frames in the order of encoding; and DISPLAY indicates the arrangement of frames in the order of display. The order of encoding of frames becomes different from that of original image due to the presence of B frames.
It is now assumed that the decoding is stopped for the encoded data B10 to P3 for the purpose of protection of the intellectual property right (for example copyright). Since motion compensation is not properly executed as in the case of FIG. 1, the images of the frames B30, B31, B40 or B41 cannot be properly executed, so that there may result perturbation of the image in each frame or interruption of the decoding operation.
In consideration of the foregoing, an object of the present invention is to provide an image processing apparatus capable of adequately processing reproduction/stopping of the image for protecting the intellectual property right (for example copyright) of the image, a method therefor and a recording medium storing an image processing program.
The above-mentioned object can be attained, according to a preferred embodiment, by an image processing apparatus/method which comprises entering image data encoded with plural encoding modes and security data for protecting the image data; discriminating, based on the security data, whether the reproduction of the encoded image data is permitted; judging the encoding mode of the encoded image data; and decoding the encoded image data based on the results of discrimination and judgment.
Also according to another preferred embodiment, there is provided an image processing apparatus/method which comprises entering image data encoded with plural encoding modes and security data for protecting the image data; discriminating, based on the security data, whether the reproduction of the encoded image data is permitted; judging the encoding mode of the encoded image data; decoding the encoded image data; and controlling the synchronization of the decoded image data based on the result of discrimination and the result of encoding mode judgment.
Also according to still another preferred embodiment, there is provided a recording medium storing process codes of an image processing method, which comprises an input step of entering image data encoded with plural encoding modes and security data for protecting the image data; a discrimination step of discriminating, based on the security data, whether the reproduction of the encoded image data is permitted; an encoding mode judging step of judging the encoding mode of the encoded image data; a decoding step of decoding the encoded image data and outputting the decoded image data; and a decoding step of decoding the encoded image based on the result of discrimination of the discrimination step and the result of judgment of the encoding mode judgment step.
Also according to still another preferred embodiment, there is provided a recording medium storing process codes of an image processing method, which comprises an input step of entering image data encoded with plural encoding modes and security data for protecting the image data; a discrimination step of discriminating, based on the security data, whether the reproduction of the encoded image data is permitted; an encoding mode judging step of judging the encoding mode of the encoded image data; an image decoding step of decoding the encoded image data; and a synchronization control step of controlling synchronization of the decoded image data based on the result of discrimination and the result of judgment of the encoding mode.
Other objects, features and advantages of the invention will become fully apparent from the following detailed description taken in conjunction with the accompanying drawings.